Cellular networks using newer radio access technologies (RATs), such as Long Term Evolution (LTE), are being developed and deployed. Networks using these newer RATs have packet switched (PS) domains configured to support PS voice calls, such as via voice over Internet Protocol (VoIP). As coverage of newer networks such as LTE networks is not universal, networks using newer RATs are often co-deployed with legacy RATs, such as second generation (2G) and third generation (3G) RATs, including Universal Mobile Telecommunications System (UMTS) networks and Global System for Mobile Communications (GSM) networks, which only support voice calls via a circuit switched (CS) domain. Accordingly, a wireless communication device can be handed over between a network, such as an LTE network, supporting PS voice calls and a legacy network supporting voice calls via a CS domain as coverage or other conditions may dictate. For example, where LTE coverage is running out, the LTE network can redirect a device to a legacy network in response to the device moving out of the coverage range of the LTE network.
A device having an active voice call supported by a PS domain of an LTE network or other network supporting PS voice calls may have to perform a handover to a legacy network during the voice call due to mobility outside of a coverage area of the serving network or other network conditions, which may merit handover. SRVCC has been defined as a procedure to allow an active voice call to be moved from a PS domain to a CS domain of a legacy network during handover of a device to a legacy network. Presently, only the device redirected to the legacy network is aware of occurrence of the SRVCC handover. As such, a device participating in the voice call can be unaware that a remote device participating in the voice call is participating in an SRVCC procedure. SRVCC is a relatively complicated and time consuming procedure on the network side. Due to the complexity of SRVCC, a device participating in a voice call via voice over LTE (VoLTE) or other VoIP connection while a remote device is performing an SRVCC handover can experience an interruption of voice packets in both uplink (UL) and downlink (DL) directions for up to 300 milliseconds, which can negatively impact user experience.